1. Field of the Invention
The invention relates to a staining apparatus for preparation of tissue specimens placed on microscope slides, comprising a plurality of stations in the form of vessels having liquid baths for receiving baskets or suspensions receiving microscope slides with the topical specimens, a means for transport of each of the baskets/suspensions to respective stations to undergo a staining process, and a control unit for controlling the staining process in accordance with a chosen program.
2. Description of the Prior Art
A staining apparatus of this type for example is known from U.S. Pat. No. 5,573,727, GB 2 196 428 A and international patent application No. PCT/NO96/00270 (WO 97/19379). For a further description of the construction and manner of operation of such an apparatus reference is made to these publications.
Such apparatuses stain both cytologic and histologic specimens according to different staining methods, depending on the type of tissue specimen that are to be stained.
In contradistinction to the cytologic specimens, the histologic specimens are embedded in advance in an embedment medium, such as paraffin, before they are cut into very thin slices of tissue specimens which are placed in a varying number on a microscope slide which is thereafter inserted into a basket or a suspension. A varying number of baskets or suspensions thereafter are placed in a heating stove to heat the microscope slides with tissue specimens to a desired temperature to melt down the embedment medium on the microscope slide, so that the tissue specimens will become stuck to the microscope slide during the transport from one bath to another during the subsequent staining process
The basket (or suspension) with microscope slides thereafter is placed in a staining apparatus for staining of the tissue specimens in accordance with a program. The known staining apparatuses, e.g. the apparatus according to U.S. Pat. No. 5,537,727, is equipped with a means, e.g. a drawer, wherein one can load a basket and choose a staining program limited to one basket at a time, and moreover limited by the time factor for the working operation carried out by the transport means at this time. The distance back to the loading drawer to fetch a new basket, and the consideration for the programs of already loaded baskets if several baskets are in a staining process, the movement time of the conveyor between the different baskets, and the circumstance that two program steps can not be carried out at the same time, involves a substantial waiting time from the moment when the drawer is loaded with a basket and until the operator is able to load in the next basket.
Further, it is of substantial importance that the microscope slides, when they are placed in the bath in the staining apparatus which does not stain, but which removes superfluous embedment medium, shall have generally the same temperature as the temperature they had in the melting-down stove. The reason for this is that when the microscope slides lose their temperature, the process for removal of the embedment medium becomes more difficult and may take up to twice as long time. (A basket without heating takes about 8 min. as compared to about 3 min. with heating.)
The known staining apparatuses with the capacity of today are not able to take into consideration the fact that the microscope slides, when they are placed in the staining apparatus, should have the same temperature as the chosen temperature in the melting-down stove, or to compensate for the fact that the temperature of the microscope slides vary, so that the process for removal of the embedment medium can be carried out in an efficient manner. This means that the operator of the apparatus has to spend time to see to it that the basket with microscope slides is sufficiently heated when it is loaded into the staining apparatus, and thereafter has to wait an additional time before a new basket can be loaded in. This entails a waste of working resources because of much waiting time when loading more than one basket with microscope slides, and because of the manual handling of the baskets from the melting-down stove and into the staining apparatus.
The object of the invention therefore is to provide a staining apparatus involving both a substantial work saving and a substantial time saving in the loading of baskets/suspensions into the apparatus.
The above-mentioned object is achieved with a staining apparatus of the introductorily stated type which, according to the invention, is characterized in that it comprises a magazine for loading and simultaneous reception of a chosen number of baskets/suspensions with microscope slides, the magazine being provided with a means for heating of the baskets/suspensions placed in the magazine.
An advantageous embodiment of the apparatus is characterized in that the heating means is arranged to be controlled by the control unit in accordance with the topical program.
By providing the staining apparatus with a magazine which can receive several baskets having associated individual programs at the same time, and which is provided with a heating means for obtaining as quickly as possible a desired temperature to melt down the embedment medium on the histological specimens, there is achieved that one does not need a separate process for preheating and melting down the embedment medium in a separate stove. This implies a substantial work and time saving, since otherwise one has to load the baskets one by one with intervals of several minutes before the apparatus can take care of the individual baskets.
The magazine has a heating chamber which is arranged such that the transport means is allowed to fetch the topical basket directly from the chamber in accordance with a given temperature and a given minimum time in compliance with different programs which also control the different steps of the basket in the process wherein removal of the embedment medium, staining of the tissue specimens and delivery of the basket take place. Since the time factor for how long the histological specimens are to remain in the heating chamber, is not limited to a maximum time, but only to a minimum time, this will give a software-wise possibility to optimalize coordination of the different programs in a quite unique manner, since several baskets with several programs will be able to be evaluated simultaneously to find the most efficient running scheme for the movements of the transport means in order to be able to prepare as many baskets as possible in compliance with the different chosen programs in the shortest possible time. the magazine will function as a loading buffer, and will be able to inform the operator when for example four new baskets can be loaded in.
The staining apparatus according to the invention also admits that the transport means can return to the magazine in the middle of the staining process with a basket at a time, and that the magazine can be heated and used as a customary heating station in the middle of a staining process before a staining bath in which it is appropriate to have heated tissue specimens.
For the histological specimens the magazine will function as a melting-down chamber for the embedment medium, whereas for the cytological specimens it will function as a mere buffer when loading more than one basket at a time. Since the cytological specimens are not damaged by being put into a heated magazine, the apparatus of course may also be arranged such that both histological and cytological specimens can be prepared in one and the same apparatus.
In an advantageous embodiment of the apparatus according to the invention, the transport means which brings the baskets from one bath to another in accordance with a program, is arranged such that it lifts the topical basket up from the vessel in question in a circular movement, so that excess liquid from the basket is simultaneously wiped off against an edge of the vessel. In this manner it is avoided that liquid from the bath is transferred to and mixed with the liquid in the next bath, or that such transfer in any case is reduced to a minimum. The construction suitably is carried out such that the basket is lifted laterally inwards towards a means having a tight bottom plate preventing dripping into other vessels during transport of the baskets, and which provides for additional removal of remaining excess liquid since the microscope slides will lie, laterally in contact with said bottom plate, in order to guide the liquid drops away from the microscope slides.
Delivery from the apparatus of a ready basket does not take place by means of a separate means for unloading, but in that the transport means brings the ready basket to a given position in the apparatus, from which the operator can take out the ready basket directly.